[simonh]

I actually don't think the observable universe is big enough, and that's been demonstrated mathematically by better people than I, but the universe as a whole including non-observable parts might be big enough.

I don't see how this is not the Bolzmann's Brain proposition. What's the difference?

>Consciousness can have a materialist explanation yet also be substrate dependent to an extent.

I suppose so, maybe there's a quantum mechanical component, but even in that case why couldn't that be built into a computer? What sort of substrate might it be that we couldn't build it into a robot for example?

[csee]

If the observable universe is too small, what about the observable universe sampled at multiple points in time? Or just an iron bar that's repeatedly sampled along a time interval, with the desired encoding changing between each sample such that the object doesn't need to undergo much change it state in order to map to distinct things. Each sample increases the number of physical states that we can create a mapping from. If we still don't have enough states, we can draw more samples over more points in time to create a longer string of bits for the mapping.

Or another way to do it would be to repeatedly sample the same object at the same point in time, and simply change the desired encoding on each sampling, e.g. on a first pass we use F_0(x), on a second pass we use F_1(x), and we concatenate the output of F_0(x) and F_1(x) into a single large bit array.

The Boltzmann Brain says that our conscious experience at the current moment is a chance quantum event. It might not even involve the whole universe, it could be a local quantum phenomenon. That seems distinct to the argument in the article, which is that physical states (quantum or otherwise) can be mapped to an arbitrary string of bits with the encoding chosen by the person doing the mapping, and the output of this mapping (which is itself a string of bits) can correspond to a computation on a Turing machine, therefore inanimate objects with sufficiently large numbers of physical states could be said to be running a proposed consciousness.exe, which leads us to an absurd/extreme form of panpsychism.

[simonh]

>The Boltzmann Brain says that our conscious experience at the current moment is a chance quantum event.

I just meant that the proposition that an iron bar might be viewed as containing a consciousness, is similar to the idea in the BB proposition that consciousnesses might arise spontaneously in random matter in space. Well they might, but that doesn't prove or refute anything about consciousness.

The bit about Boltzmann's Brains possibly outnumbering real evolved brains is a separate philosophical question I didn't mean to address, and I apologise for the confusion.